As I understand it things made under the influence of drugs seem really good at the time. However when you look at it when your not high, you soon realise it's actually really bad. Drugs aiding creativity is a myth.
I think this is a very rigid statement. My drawings have been enhanced
noticeably by psilocybin mushrooms. The whole method by which I approach the human form changed considerably after a very lengthy drawing session and a heavy dose of psilocybin. While on the drug I created one of my most technically impressive illustrations. And during its creation it was as though I was channeling some external intelligent force. It is a very beautiful experience, and one that can not be so easily dismissed. Drugs certainly shape and impact art, particularily music. Its effect is obviously subjective... But I can guaranty that The Beatles, Jimmi Hendrix, Bob Dylan, The Doors, etc. etc. would have made much different music had they not indulged in psychedelics.
That being said, making a film is not like drawing, or making music. Your creativity is not the
only tool you have when making a film. You need to reason, plan, contemplate, operate complicated equipment, and so on. It would be very hard to stay focused. I think kgasser had the right idea when he said, come up with the ideas and the concepts while on the drug and then actually create the film later, while sober.
Psychedelics feed your ideas. But when it comes to something as demanding as shooting a film, chances are they would make you pretty useless. Unless of course you were a genius with a camera and an experienced tripper, then perhaps you could make some experimental, improvisational film. Chances are it would be shit, but I suppose its possible.